The present invention relates to a drying apparatus and more particularly to an improvement of a drying apparatus having an open-ended drum supported rotatably about a horizontal axis.
In conventional types of drying apparatus, an air inlet port having a filter is provided, for instance, in the front part or panel of the cabinet, while an exhaust port having a filter is provided at the central portion of the rear wall of the open-ended rotatable drum. The filter in the air inlet port catches any dust in the air which is introduced through the air inlet port, and the filter in the exhaust port catches any lint contained in the exhaust air. With such a construction, however, although the inspection and cleaning of the air inlet portion can be carried out easily, inspection and cleaning of the filter in the exhaust port are difficult, because in its rearward position of the drum it is hardly accessible.
Recently, a construction has been proposed (it is not a part of the prior art) wherein the air inlet port with its filter and the exhaust port with its filter are both provided in the front part or panel of the cabinet at a position adjacent to the door on both sides thereof for facilitating the inspection and cleaning operation. In this case, the air inlet port communicates with an air path defined between the side wall of the cabinet and a peripheral surface of the drum, while the exhaust port communicates with the interior of the same drum. It is desirable from the viewpoint of operational convenience that the opening for placing materials or clothes into the drum and taking them out of the drum is disposed at the front portion or panel of the cabinet.
Therefore, the exhaust port is positioned on one side of the door on the front panel in such a way as to be facing the peripheral area of the interior of the drum. On the other hand, even though clothes or materials to be dried are piled up adjacent to the lower part of the inner peripheral wall of the drum when the latter is not rotating, those on the bottom of the inner peripheral wall are carried along with the drum and are lifted to the upper part of the drum during operating or rotating of the drum, and they then separate from the inner surface of the drum to roll down or fall downwardly under the influence of gravity.
Thus, materials to be dried are tumbling within the interior of the drum into which hot air is being supplied, and then these materials are rapidly deprived of water.
On observing the distribution of materials in the drum during rotation of the latter, the distribution of materials is dense in that half or side of the interior of the drum to which materials at the lower port on the inner surface are carried, and the distribution of materials in the other half or side of the drum is sparse, since materials carried to the upper part in the interior of the drum drop downwardly before reaching the top part in the drum. Assuming here that the exhaust port is provided at a position facing the region where materials to be dried are piled up densely, the flow resistance against air becomes impractically large so as to reduce the rate of flow of hot air flowing through the materials to be dried, resulting in a lowered drying efficiency.
As a result of this construction, a desired amount of supplied hot air cannot be attained, and this also increases the tendency of the heater which produces the hot air to overheat and also undesirably shortens the life of this heater. In addition, it is necessary to provide a larger hot air supply capacity in order to get a large enough amount of hot air.